This invention relates to vane compressors adapted for use in air conditioning systems or the like, and more particularly to vane compressors provided with improved camming surfaces which minimize torque fluctuations.
As known e.g. from U.S. Pat. No. 3,834,846, a vane compressor in general comprises a drive shaft arranged to be rotated by a prime mover, a rotor arranged for rotation in unison with the drive shaft and having an outer peripheral surface formed therein with a plurality of slits, a plurality of vanes radially movably fitted in the slits of the rotor, and a pump housing having an inner peripheral surface formed as an endless camming surface and in which the rotor and the vanes are received. The rotor, the vanes and the pump housing cooperatively define therebetween at least one pumping chamber. As the rotor rotates, gaseous fluid such as refrigerant gas is sucked into the pumping chamber, compressed therein and discharged therefrom.
In the above vane compressor, the endless camming surface of the pump housing, along which the vanes slidingly move in unison with the rotating rotor, has an elliptical cam profile in the type where the pump housing has two pumping chambers defined therein, and a circular cam profile in the type where the pump housing has a single pumping chamber defined therein.
However, conventionally no particular consideration was given to minimizing fluctuations in the torque acting upon the rotor in designing the cam profile of the endless camming surface. Therefore, the conventional vane compressor has large torque fluctuations during each cycle of suction, compression and discharge of fluid, which causes occurrence of operating noise and vibrations of the compressor during operation of the compressor.